The present invention relates to a method for making breads, more specifically, by incorporating potassium bromate as an oxidizing agent into a bread dough, wherein the resulting baked breads are free from residual bromate.
Potassium bromate has been widely used in the world since 1910s when it was recommended as a bread improver in the United States. In Japan, there is a guideline for use of potassium bromate, stating that “potassium bromate is limited to use for yeast leavened bakery products in an amount of up to 0.03 g (as bromate) per kg of wheat flour (i.e., 30 ppm based on wheat flour) and should be decomposed or removed before completing final products,” that is, potassium bromate must not remain in the products after baking.
In conventional techniques, prevention of residual bromate in bakery products has been accomplished, either by using sufficient time for fermentation and baking of a dough to ensure complete chemical reaction of bromate or by incorporating a reduced amount of potassium bromate, or both.
The inventors of the present invention have already developed a method for prevention or reduction of residual bromate in bakery products by incorporating ascorbic acid (see, e.g., JP 8-116857 A).
The limitation “bromate should be decomposed or removed” or “bromate must not remain” in the Japanese guideline is intended to mean that bromate cannot be detected when measured by the most sensitive analysis at the time of the measurement, i.e., that bromate is below the detection limit. In view of this limitation, the inventors of the present invention have attempted to incorporate ferrous sulfate in the step of preparing a dough using potassium bromate and have succeeded in reducing residual bromate in bakery products to less than 3 ppb, a non-detectable level as measured by their developed ultra-sensitive HPLC (high performance liquid chromatography) analysis with a detection limit of 3 ppb for bromate in the baked breads (see, e.g., Japanese Patent No. 3131898).
However, the term “free from residual bromate” or “prevention of residual bromate” as used herein is intended to mean that bromate does not remain in an amount greater than 1 ppb, the “detection limit for bromate” as measured by further improved state-of-the-art HPLC analysis at the filing of the present invention.
However, the above conventional techniques neither confirm their efficacy for complete removal or significant reduction of residual bromate in breads, nor disclose the incorporation of potassium bromate as an aqueous solution. Further, in these conventional techniques, ferrous sulfate is incorporated in an amount of 50 ppm to 370 ppm based on total wheat flour required to prepare a dough, which amount significantly exceeds the range acceptable for the breads of the present invention to maintain the loaf volume, flavor and taste of breads.